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here is a response from tom wilson, president of second wind. we sell his products and have had nothing but good feedback from customers. I also have one in my house installed on the cold air return and have had no problems with my aprilaire media filter deteriorating.

Second Wind systems are instructed to be installed 36 away from non-UV materials if at all possible. Non-UV materials should be shielded to prevent degradation due to UV exposure. Aluminum duct tape does a great job, as does tinfoil! Drain pan manufacturers have fixed many of the issues by moving to UV resistant materials to prevent breakdown. Lower UV systems (again 24V systems) do not create the same damage a HO system like the 2000 models lamps could do. I would never advise to install a 2000 or 1000KCS next to a filter  it would melt if it was not UV-resistant like our 9000 series units.

The return plenum is an ideal place to install a UV system as the air is moving the slowest in that part of the system, providing the best exposure time to break down the microscopic contaminants. The comment about not enough time for exposure is a statement that we love to engage because the time required to kill these contaminants that are smaller than can be seen is often achieved in the first pass (see above). Our PCO system does not have a chamber so we create the field inside the entire duct with our 18 lamps and create a massive UV bath of 72 x duct cross-section area.

So, you have confirmed exactly what this thread is about - UV lights will destroy any materials made of hydrocarbons exposed to the UV lights. This is a major problem since buyers are not informed of this potential damage or the costs involved.

So, you have confirmed exactly what this thread is about - UV lights will destroy any materials made of hydrocarbons exposed to the UV lights. This is a major problem since buyers are not informed of this potential damage or the costs involved.

Proper installation will result in no damage, far enough up in the return drop and you have no direct exposure to the light, put shielding in to protect non uv resistant materials or cover in foil tape. Those filte earlier in this thread must have been right next to the bulb. The company I work for installs a lot of uv lights and with proper installation and educating the customer a little we never have any problems. But I have seen them installed wrong by the other guys and it usually results in the filter deteriorating, but I've never seen them as bad as the photos posted earlier.

UV Lamp location is key

Originally Posted by breathe easy

Has anyone else had problems with UV lights, EAC's and the other "new" air cleaners deteriorating the hydrocarbon based components of their HVAC systems? I just had another customer show me a filter that looked like Swiss cheese after being exposed to a UV light. The UV light and the ozone will react with any plastic materials such as filters, pans, wire, mastic, flex duct, etc. I would like to know how widespread this problem is and what people are doing about it.

The placement of the lamp (s) I believe is key. Lamps should be installed on the output side of the coil (Per Carrier pub:63UV-LA3). I sell and install UV lamps on occasion, I even have installed one in my home. I have never had a problem with plastics in the system, I believe that the new plastic pans are uv and chemical resistant. Flex duct might be a problem but I have not seen that as most of the systems I work on are metal pipe or ductboard. I use a TIF 3710 to check uv lamp operation; when installing a new bulb I mark the readings on the coil, averaging readings on both front and back side of coil. If the bulb is less than 1 year old and reading low because the bulb is dirty I clean it with alcohol, carrier sells a cleaning kit. I have seen a big difference in only 6 month of using a uv lamp on some systems. Usually the coil and pan look like new. I also recommend a good filter, like an Aprilaire, be installed at the unit. I have never seen an Aprilaire filter degraded by uv light, even when installed directly on intake of a fan coil. I always install the uv lamps between the coil and blower not the coil and filter, even so when you remove the filter you still get a dose of uv radiation but I have not seen any harm even after a year of same filter being exposed to uv.